The overall objective of this grant is to provide information and equipment that will facilitate the use of hyperthermia as a clinical tool. The specific aims for the 1985-1989 period are: 1. To determine the response of tumors to drug and heat as a function of pH. 2. To determine mechanisms for the increased interaction between many drugs and heat at low pH. 3. To determine the influence of thermotolerance on drug-heat interactions and to see if heat-drug cross resistance can be used as an assay for drug response. 4. To determine if ultrasound has effects on heat-drug interactions over and above those from heat alone. Drugs: Adriamycin, bleomycin, BCNU, cis-platinum Experimental techniques include: tissue culture, transplantable mouse tumors (RIF, EMT-6, B-16 melanoma), FACS, gel electrophoresis, fluorescent dyes, ultrasound and radiofrequency heating